The evolution of the post-cranial dermal skeleton vascular system in Testudinata and Pseudosuchia: Phylogenetic constraints versus eco-physiological adaptations

CLARAC, FRACOIS; SCHEYER, TORSTEN; DESOJO, JULIA B.; CERDA, IGNACIO A.; SANCHEZ, SOPHIE

PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY B-BIOLOGICAL SCIENCES

ROYAL SOC

Lugar: Londres; Año: 2020

0962-8436

Studies on living turtles have demonstrated that their shield was involved in the resistance to hypoxia during apnea via bone respiratory acidosis buffering; a process which is complemented with cutaneous respiration in the soft-shell turtles. Ecophysiological functions have been identified as well in crocodylian osteoderms. The latter have also proved to be involved in respiratory acidosis buffering during prolonged apnea and heat transfers when basking. Although diverse, these functions rely on one common factor: the degree of vascularisation of the post-cranial dermal skeleton. Here we test whether the above ecophysiological functions played an adaptative role in the evolutionary transitions between land and aquatic environments in both Pseudosuchia and Testudinata. To do so, we measured the bone porosity as a proxy for the degree of vascularity in a set of dermal plates before performing phylogenetic comparative analyses. For both lineages, the dermal plate porosity obviously varies depending on the animal lifestyle but these variations prove to be highly driven by the phylogenetic signal.